USF Libraries
USF Digital Collections

Is the river continuum concept applicable to a lower montane stream in Monteverde, Costa Rica?

MISSING IMAGE

Material Information

Title:
Is the river continuum concept applicable to a lower montane stream in Monteverde, Costa Rica?
Translated Title:
¿Es el concepto de la serie continua del río aplicable a una quebrada más baja en Monteverde, Costa Rica? ( )
Physical Description:
Book
Language:
English
Creator:
Picetti, Michael A
Publisher:
s.n.
Place of Publication:
Monteverde

Subjects

Subjects / Keywords:
Potable water
Agua potable
Quebrada Máquina
Monteverde
Genre:
Books / Reports / Directories   ( local )
Books / Reports / Directories   ( local )

Notes

Language:
Inglés/English.

Record Information

Source Institution:
University of South Florida Library
Holding Location:
University of South Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
usfldc doi - M36-00494-ML-1105
usfldc handle - m36.494-ml-1105
System ID:
SFS0001976:00001


This item is only available as the following downloads:


Full Text
xml version 1.0 encoding UTF-8 standalone no
record xmlns http:www.loc.govMARC21slim xmlns:xsi http:www.w3.org2001XMLSchema-instance xsi:schemaLocation http:www.loc.govstandardsmarcxmlschemaMARC21slim.xsd
leader 00000nas 2200000Ka 4500
controlfield tag 008 s2006 xx |||| |||||| eng
datafield ind1 7 ind2 024
subfield code a M36-00494-ML-1105
040
FHM
1 100
Picetti, Michael A.
0 242
Es el concepto de la serie continua del ro aplicable a una quebrada ms baja en Monteverde, Costa Rica?
245
Is the river continuum concept applicable to a lower montane stream in Monteverde, Costa Rica?
260
g El 9 de junio 2006/June 9, 2006.
Monteverde
546
Ingls/English.
655
Books / Reports / Directories
2 local
653
Potable water
Agua potable
Quebrada Mquina
Monteverde
720
Scanned by Monteverde Institute.
EAP
773
The State of Water in Monteverde, Costa Rica: A Resource Inventory.
049
FHmm
4 856
u http://digital.lib.usf.edu/?m36.494-ml-1105



PAGE 1

Is the River Continuum Concept applicable to a lower montane stream in Monteverde, Costa Rica? Michael A. Picetti University of California, Berkeley Department of Environmental Science, Policy, and Management Molecular Environmental Biology EAP Tropical B iology and Conservation, Spring 2006 9 June 2006 __ _____________________________________________ _______________________________ Abstract The River Continuum Concept (RCC) is a model that attempts to explain the changes in physical and biological character istics of lotic ecosystems that occur from the headwaters of a streams outside the temperate zone is contentious. The RCC provides a theoretical distribution and re lative proportions of each functional feeding group (FFG) at different locations (stream orders) within the stream. I evaluated the applicability of the RCC to the Quebrada Mquina, which flows through the forest surrounding the Estacin Biolgica Montever de, by comparing FFG proportions, taxa richness, relative abundances and diversity. To do this, I sampled nine sites and collected aquatic macroinvertebrates. I then identified them using a stereoscope and referred to FFG identification keys (to family lev el) to assign macroinvertebrates to their appropriate FFG. The FFG proportions for the first order conformed very well to the RCC while the proportions for the second order completely contradicted the model. The mean number of taxa per order was essentiall y the same, but the first and second orders had higher mean relative abundances of individuals compared to the third order. The third order, however, was the most diverse. The FFG proportions indicate that the RCC is at least applicable to the Quebrada Mq uina although the model clearly did not hold throughout the entire stream. Resumen El Concepto Ro Continuo (RCC) es un modelo que trata de explicar los cambios fsicos y biolgicos de ecosistemas acuticos que ocurren del origen y al final de los ros o quebradas. Debido a su origen de la zona templada, hay es una contencin si el RCC es aplicable a las quebradas que no estan en la zona templada. El RCC provee una distribucin terica y proporcin relativa para cada grupo functional de alimentacin (FFG) en diferentes posicines (ordenes de quebrada) de la quebrada. Yo evalu si el RCC es aplicable a la Quebrada Mquina que fluye por el bosque a cerca de la Estacin Biolgica Monteverde por comparando las proporcines FFG, taxn cantidad, abundancias relat ivas y diversidad. Para hacer esto, yo colect muestras de macroinvertebrados acuticos de nueve sitios. Yo los identifiqu con un microscopio y yo refer a un libro de identificacin FFG (a nivel familia) para asignar los macroinvertebrados a sus FFG apro priados. Las proporcines FFG del primer orden se conformarn muy bien al RCC pero las proporcines del segundo orden contradijern completamente el modelo. El nmero promedio de taxones de cada orden fue esencialmente lo mismo, pero el primer y segundo or denes tuvieron promedias ms altas de abundancias relatives de individuos compar al tercer orden. El tercer orden tuvo la diversidad ms mayor. Las

PAGE 2

RCC applicability to a lower montane stream Picetti 2 proporcines FFG indican que el RCC es por lo menos aplicable a la Quebrada Mquina aunque el modelo no fue vlido por todas partes de la quebrada. ______________________________________________________________________________ Aquatic macroinvertebrates have played an integral part in stream ecology By definition, the term tebrate fauna capt ured by a 500 micrometer net or sieve (Hauer and Resh 1996). Macroinvertebrates within lotic ecosystems (those pertaining to running waters such as streams an d rivers) serve as a fundamental link between organic matter and primary consume rs and are also very diverse due to the abundance and variety of microhabitats found within streams. The creation of such microhabitats can be attributed to change s in physical and biological riverine char acteristics that occur from the headwaters (origin) to the mouth (Thorp and Covich 1991). Specific types of changes occurring downstream tend to include the widening and deepening of the river as well as increasing water turbidity (Thorp and Covich 1991). In addition, canopy cover generally decreases subst antially downstream resulting in less stream shading and allowing more sunlight to reach the water su rface. This facilitates greater photosynthetic production near the water surface and an ov erall increase in autochthonous (internally produced) input (Thor p and Covich 1991). Subsequently, the macroinvertebrate fauna undergo significant changes in species (or higher taxa level) composition, relative abundances and functional feeding group distribution (Thorp and Co vich 1991). The River Continuum Concept (RCC ) attempts to explain this variation in a holistic manner within the context of a longitudinal gra headwaters (first order section) to its mouth which is considered the higher order section (Vannote et al. 1980). The RCC was initially developed for pristine and relatively undisturbed temperate North American streams and as a result its applicability to streams in non temperate zone regions of the world is uncertain (Minshall et al. 1985). There are three fundamental assertions that form the framework of the R CC (Thorp and Covich 1991 ). The first is that stream macroinvertebrate communities occur in response to a continuous gradient of abiotic factors (e.g. stream volume, substrate size etc) present from the headwaters to the mo uth. The second feature is that riparian zone or the surrounding biotic and geomorphic catchment area that funnels materials into the ecosystem such as water an d nutrients. Lastly, the third feature maintains that the nature of a downstream community is linked with processes occurring upstream (Thorp and Covich 1991). Besides the three fundamental assertions of the RCC, one of the most important invertebrate eco logical aspects addressed is the change in relative abundance of functional feeding groups (FFG) and their food resources ( Thorp and Covich 1991). An FFG distinguishes insect taxa that perform different functions within aquatic ecosys tems with respect to p rocessing of nutritional resource categories (Merritt and Cummins 1996 a ). The F FG categories are which include sub (CF) and (P) (Thorp and Covich 1991). Shredders mo stly feed on coarse particulate organic matter (CPOM) which consists of litter accumulations of leaves, bark, twigs, and other plant parts greater than one millimeter in size. Collectors tend to consume fine particulate organi c matter (FPOM) that comprises unattached living or detrital material which is between 0.5 micrometers and one millimeter in size and is produced by biolog ical reduction of CPOM. Grazers mainly feed on periphyton which includes

PAGE 3

RCC applicability to a lower montane stream Picetti 3 primarily attached algae and associated material growing on various su rfaces such as plants or rocks. The prey that predat ors capture are usually smaller species or juveniles of larger species (Merritt and Cummins 1996 a ). Based on the existing FFG categories and general stream tr end s, the RCC makes predictions for relative abundances of FFG in accordance with riparian habitat changes downstream (Thorp and Covich 1991). One prediction is tha t shredders and collectors will dominate headwater streams since they usually contain dense tre e canopies with a lot of stream shading. In mid order reaches further downstream, the proportion of shredders should decline drastically and give rise to a much more abundant scra per assemblage due to increased autoch thonous inputs serving as food. And for higher order sec tions of the stream, collectors (especially collector filterers) are predicted to be the most prevalent. In spite of the RCC predictions and numerous studies done to test them, there is still ongoing debate about its applicability outside the temperate zone. Statzner and Higler (1985) contend that the RCC is globally applicable. Furthermore Greathouse and Pringle (2005) conducted a study in Puerto Rico and considered the RCC to be applicable to running waters on tropical islands. However, in this study, my objective is to inves tigate the applicability of the RCC to the Quebrada Mquina, which i s a neotropical mainland stream in Monteverde, Costa Rica. I intend to e valuate RCC applicability based primarily on proportions and distri bution of richness, relative abundances of individuals, and diversity starting upstream (first order) and moving downstream (third order). Materials and Methods Study area The study was conducted a t nine sites along the Quebr ada Mquina whic h is located in lower montane forest (1450 1600m) surrounding the Estacin Biol gica Monteverde. I collected samples and identified aquatic macroinvertebrates between 15 May and 24 May. For the reach of the Quebrada Mquina that I studied, there were first second, a nd third order sections and within each order I sampled three sites. The topmost site (first order) was located above an unnamed waterfall and the bottom most site (third order) ended 15 meters upstream of a small concrete dam Besides the dam the stream was relatively undisturbed and th e sites were accessible by walking along the Sendero Jilguero and then through or along the streambed. Each chosen site was delineated by measuring a 10 meter transect line and marked with blue flagging tape at t he beginning and end of each site. During the sampling period, the water level within the stream was relatively low and it was necessary to choose sites with sufficient volumes of water. My main objec tive was to sample a variety of microhabitats (i.e. rif fl es, leaf litter, sandy bottoms, pools and rocks) at each site to obtain a representative sample Before I began to sample, I made qualitative observations ab out physical characteristics of the stream site. At each site, I measured and recorded wat er te mperature, elevation, mean channel width and mean wate r depth for each microhabitat as well as mean stream velocity. Mean values were averaged over all micr ohabitats sampled at each site. I used a thermometer, altimeter and 100 m eter tape measure to measur e temperature, elevation, and width/depth, respectively. Stream velocity was estimated by tying a string of known length to an empty plastic vial and using a chronometer to determine the time that elapsed before the string straightened out. In addition, I est imated percent canopy cover (using ranges of 0 20%, 21 40%, 41 60%, 61 80% and 81 100%) and also observed substrate type and attempted to classify substrate by

PAGE 4

RCC applicability to a lower montane stream Picetti 4 estimating particle diameter ranges that I assigned as sand (0 1mm) 0 10cm pebbles, 11 20cm, 21 50cm, 51 80 cm and greater than 80cm (Allan 1995). In typical RCC streams, the headwaters are us ually dominated by larger rocks (boulders) and in higher order sections the main substrate type is generally sand or smaller pebbles. By crudely estimating r elative proportions of each size class, I was able to use the Wentworth Scale (Minshall 1984) to later categor ize the observed substrate using an est ablished classification system (Tables 1 2). Sampling I sampled by using a strainer and pressing it along the st ream bottom against the current and washing off stones and brushing various substratum (e.g. gravel, leaves, etc) into the strainer with my hands. This process usually only took a few minutes because the strainer would then be completely full. At th at point, I emptied out the contents into a tray and sorted through them using a pair of forceps for 20 30 minutes After finding a macroinvertebrate, I placed it into a vial containing 80% ethanol which preserved the specimen. I placed all macroinvertebra tes into a separate vial for each site. I sampled 3 4 microhabitats per site depending on the water level at that site and on the time it took to finish searching through the tray. I spent one and a half hours sam pling at each site and my sampling times ra nged between 8:30AM and 4:30PM This wide variation in sample times, however, should not have significantly biased either the richness or diversity of the samples I obtained (R. Chaves, pers. comm. ). After I finished sampling, I brought the vials back to t he lower lab for identification. Identification I identified each individual vial of macroinvertebrates within 24 hours of obtaining the sample by using a dissecting microscope in the lo wer lab. Roldn (1988) served as the primary reference that I consult ed to aid in identification. With the exceptions of Decapoda and Amphipoda (Orders) as well as Staphylinidae and Planariidae (Families), individuals were identified to genus level with either positive identification or the assignment of morphospecies. As i ndividuals were being identified to their appropriate taxonomic level, I recorded abundances for each taxon. Next, I assigned the v arious taxa to their associated functional feeding groups (FFG) based on lotic macroinvertebrate FFG identification keys (to family level) that were in Merritt and Cummins (1996 b ). To analyze differences in distribution of FFG, differences in t axa richness and differences in abundances of individua ls between orders, I conducted a Chi Square test, one way ANOVA and Kru skal Wa llis te st, respectively using JMP IN 4.0.4 I also calculate d stream order diversities with the Shannon Wiener index using Quantitative Analysis in Ecology. Results In total, I collected 520 individuals belonging to 24 families and two orders (Amphipoda and D ecapoda) that were not identifiable to family level. Overall, ten orders were also represented but the most important taxonomic levels related to my study were at the family and genus level. Family level identification was ( Table 3). The FFG distributions were s ignificantly different among the three stream orders ( Chi square, 2 = 110.47 df= 8 p<.0001; Fig .1 ). The shredders showed the most dramatic change in distribution as they accounted for over half of all ind ividuals in the first order sites sampled whereas they only constituted 22% of the total number of individuals for all third order sites s ampled. The collector gatherers also showed substantial change in distribu tion as they increased from 23% of

PAGE 5

RCC applicability to a lower montane stream Picetti 5 the total sample in the first order to comprise 42% of all individuals in the third order sample. The collector filt erers also demonstrated an overall increase of 9% from the first to the third order. Predators also increased overall from 11%% to 19% from the first to the third order. Shredders/predators, however, showed a slight decrease to 3% for the third order. In terms of t axa richness, I inferred that the mean number of macroinvertebrate taxa observed for each order is very similar (one way ANOVA, p=0.83; Fig 2 ). Relative abundances of individuals obviously fluctuated between orders, but the most conspicuous pattern was th at Amphipods dominated the first two orders while they declined dramatically in the third order (Fig. 3 5 ). The mean relative abundances o f macroinvertebrate individuals was higher for the first and second orders compared to the third order ( Kruskal Wallis 2 =33.72, df=2, p< .0001 ; Fig. 6 ). There were 168 individuals in the first order, 210 individuals in the second and 142 individuals within the third. The Shannon Wiener diversity index incorporates both taxa richness and individual abundances. The third o rder had the highest overall diversity based on values for Shannon diversity ( ), Maximum Shannon diversity (H max ) and E ). There was a significantly lower diversity for the first and second orders relative to the third (Hutcheson t t est, t (1 2) = 0.44, (1 2) =350, p (1 2) >.05; t (1 3) (1 3) =303, p (1 3) <.05; t (2 3) (2 3) =342, p (2 3) <.05). Discussion The most important results were the observed relative proportions of FFG for the first stream order and more generally, that there were changes in FFG taxa distribution throughout the stream orders o f the Quebrada Mquina (Fig. 1). B y observing the FFG proportions at each order it is easier to attempt to explain the fluctuations in their proportions along the longitudinal gradient based on ecologi cal and behavioral characteristics In lower order stream sections the RCC predicts that collectors and shredders will be the most abundant FFG and dominate that particular microhabitat community (Thorp and Covich 1991). The results confo rmed extremely w ell to this pr ediction as collector filterers, collector gatherers and shredders collectively accounted for 84% of all the i ndividuals of first order sites (Fig. 1). These FFG gather, filter and break down coarse particulate organic matter (CPOM) which is especially abundant in low order stream sections due to high allochthonous input (e.g. leaves, twigs) from sources outside the stream in the riparian zone. The second order (mid order) section of the stream based on RCC predictions is expected to see shred ders diminish drastically and allow for the establishment of a substantial grazer fauna (Thorp and Covich 1991). The rationale supporting this predicti on is that the river will widen and permit more sunlight to reach the water surface which would facilitat e increased autochthonous production particularly from benthic algae. (Thorp and Covich 1991). The FFG proportions for the second order, however, greatly contradicted these predictions since shredders only decreased by 6% and still comprise d 50% of total i ndividuals while there were no grazers present at all. Grazers were conspicuously absent from all nine sites. However, algae was never observed at any of the nine sample sites either which could explain their absence since grazers primarily feed on algae ( periphyton) (Merritt and Cummins 1996b). It is not possible to state that the relationship between t he lack of algae and absence of grazers is causal, but there is a correlation In addition, the entire stream reach sampled was heavily shaded by dense tree canopy cover that ranged between 81 100% for eight of the nine sample sites (Table 1). This is also in conflict with the proposed increase in sunlight reaching the water surface and it is very likely that the lack of

PAGE 6

RCC applicability to a lower montane stream Picetti 6 algae can be attributed to heavy strea m shading. Since the riparian vegetation was still very dense for second order sites, it is possible that there is still a significant input of allochthonou s matter which could enable the shredder population to re main relatively abundant. The third order ( higher order) section of the stream regarding RCC predictions expects collector filterers to make up the vast majority of the ecosystem (Thorp and Covich 1991). Associated habitat changes with higher order streams include deepening of the river bottom so t hat it will not receive sunlight and additional widening which prevents any considerable input of allochthonous matter (Thorp and Covich 1991). Collector filterers are able to thrive at this location because of the great quantities of FPOM and finer organi c particles that are available as a result of processing upstream by shredders (Thorp and Covich 1991). Subsequently, I believe most of the CPOM would have already been processed and therefore this lack of food for shredders could be responsible for the dr astic decline as observed in the third order relative to the first two orders. The FFG proportions for the second order show that collector filterers only constitute 14% of the total number of individuals present. However, when considered together, collect or filterers and collector gatherers account for 56% of all individuals which does not meet RCC expectations nearly as well as the first order results, but still does so to a lesser extent. The proportion of predators increased to 19% in this order and I speculate that the increase could be due to higher diversity le vels which c ould potentially provide a greater variety of prey for specialist predators Similarly for this order, the habitat conditions did not conform to those idealized changes put forth b y the RCC since the stream may have only widened and deepened by a negligible amount, if at all (Table 1). This recurring pattern of a relatively static set of habitat conditions as movement occurs down the longitudinal gradient may help to explain the ver y similar mean number of taxa for each order since the habitat conditions that govern feeding and other activities are fairly constant and can only sustain a limited number of taxa competing for similar resources. However relative abundances of individual s showed substantial differences between orders. The first and second orders had much higher mean relative abundances than the third and this can be explained in part due to the high abundances of Amphipoda in the first (93 individuals) and second orders ( 104 individuals), respectively. They accounted for approximately 50% or more of the total number of individuals in both these orders, but in the third order there were only 31 present. Consequently, the Amphipods in the third order made up less than 25% of all individuals. This abrupt decline in Amphipod abundance definitely contributed to the decrease in total third order abundance and therefore to the lower mean abundance as well. Perhaps the sharp decline of Amphipods observed for the third order can be attributed to less available CPOM compared to the first and second order stream locations. Since Amphipods are shredders, it is not likely that much CPOM would reach the third order section without being broken down or processed upstream. Conversely, Simul ium showed a dramatic increase in abundance for the third order as 13 individuals were present whereas there were none in the first order and only one in the second. This increase for Simulium can be explained by the fact that there was probably a more abu ndant supply of FPOM resulting from processing upstream and suspended organic particles that they consume as collector filterers It is difficult to explain why the second order had the greatest total abundance, but maybe these sites contained more micr oha bitats than the other orders which could sustain more individuals. In terms of diversity the third order had the highest values. Stream health clearly affects diversity and in general, higher quality and healthier streams will contain higher levels of div ersity. In the third order, it appeared that the stream had been influenced slightly by

PAGE 7

RCC applicability to a lower montane stream Picetti 7 anthropogenic influences as the number of Anacroneuria had decreased by more than 50% compared to its first order abundance. However, this does not mean that conditions were so poor that nothing could survive since Anacroneuria is an extremely sensitive insect to water impurities and anthropogenic influences. It has been suggested that mid order streams have the greatest variety of energy inputs and thus may peak in biol ogical diversity (Allan 1995). conceivable that the third order may have the greatest variety of energy inputs contributing to the highest diversity measures. Anoth er issue to consider for the Quebrada Mquina that may skew results is that of scale. Vannote et al. (1980) created a diagram with relative proportions of FFG associated with various stream orders which illustrates at which order (approximately) the propos ed habitat changes tend or rivers are most likely to occur at the section where the river is of fifth order. Clearly, the reach of the Quebrada Mquina studied would not have demons trated any especially significant changes even if it was an ideal temperate zone stream to which the RCC was known to apply. Consequently, it is difficult to draw any conclusions since it is possible that there are more data downstream which could either f urther affirm or contradict the applicability of the RCC. Due to the fact that there were differing distributional patterns among stream orders and that the first order FFG proportions conformed well to the model, I would conclude that the RCC is at least applicable to the Quebrada Mquina but does not hold for t he entire stream by any means. One major source of bias in the study was the choice of sample sites that was unavoidable. Although I did walk through the streambed and managed to climb over and aro und debris, fallen trees and rocks, there were certain areas that were inaccessible and thus prevented me from obtaining truly random samples. Also, it is not always possible to categorize macroinvertebrates int o a single FFG since many are generalist feed ers especially in the tropics (Tomanova et al. 2005). In addition, diets of many macroinvertebrates may vary seasonally, during different life stages, and also based on resource availability. As a result, assi gnment to a single FFG does not accurately indi cate the functional role of certain taxa (Tomanova et al. 2005). To more accurately assess the applicability of the RCC, future studies wou ld be best served by sampling a larger stream or even a river and to potentially analyze gut cont ents of macroinverte brate taxa. Although it would be much more time consuming, such an anal ysis would allow the researcher possible. Acknowledg e ments I would like to start by expressing my gratitude to R amsa C haves because without her my project would not have been possible. Thank you so much for all of your support, enthusiasm, encouragement, advice and your endless patience in helping me identify macroinvertebrates in the lower lab. Muchas gracias! Also I want to thank Ruth Salas for coming with me to make my preliminary observations in the stream and for all the statis tical help she provided. In addition, I would like to thank Fede Chinchilla for his contagious sense of humor and jokes that always kept the group loose. And finally, I would like to say thank you to el jefe, Frank Joyce for making this such an amazing and enjoyable experience in Costa Rica.

PAGE 8

RCC applicability to a lower montane stream Picetti 8 Literature Cited Allan, J.D. 1995. Stream Ecology: Structure and function of running waters. Chapman & Hall, London. Greathouse, E.A., and C.M. Pringle. 2006. Does the river continuum concept apply on a tropical island? Longitudinal variation in a Puerto Rican stream. Can. J. Fish. Aquat. Sci. 63 :134 152. Hauer, F.R., and V.H. Resh. 1996. Benthic Macroinvertebrates. In F.R. Hauer and G.A. Lamberti (Eds.). Methods in Stream Ecology, pp. 339 369. Academic Press Inc. Merritt, R.W., and K.W. Cummins. 1996a. An Introduction to the Aquatic Insects of N orth America. Kendall/Hunt, Dubuque, Iowa. Merritt, R.W., and K.W. Cummins. 1996b. Trophic Relations of Macroinvertebrates. In F.R. Hauer and G.A. Lamberti (Eds.). Methods in Stream Ecology, pp. 453 474. Academic Press Inc. Minshall, G.W. 1984. Aquatic insect substratum relationships. In J.D. Allan (Ed.). Stream Ecology: Structure and function of running waters. Chapman & Hall, London. Minshall, G.W., R.C. Petersen, K.W. Cummins, C.E. Cushing, D.A. Bruns, J.R. Sedell, and R.L. Vannote. 1985. Developments in stream ecosystem theory. Can. J. Fish. Aquat. Sci 42 :1045 1055. Roldn, G. 1988. Gua para el estudio de los macroinvertebrados acuticos del Departamento de Antioquia. Pama editors, B ogot, Colombia. Sall, J., Lehman, A., and Creighton, L. 2001. JMP Start Statistics. Duxbury Thomson Learning. Statzner, B., and B. Higler. 1985. Questions and Comments on the River Continuum Concept. Can. J. Fish. Aquat. Sci 42 :1038 1044. Thorp, J.H., and A.P. Covich. 1991. Ecology and Classification of North American Freshwater Invertebrates. Academic Press Inc. Tomanova, S., E. Goitea and J. Helesic. 2006. Trophic levels and functional feeding groups of macroinver tebrates in neotropical streams. Hydrobiologia. 556 :251 264. Vannote, R.L., G.W. Minshall, K.W. Cummins, J.R. Sedell, and C.E. Cushing. 1980. The river continuum concept. Can. J. Fish. Aquat. Sci. 37: 130 137.

PAGE 9

RCC applicability to a lower montane stream Picetti 9 (c) Figure 1. Functional feeding group compositions o f (a) first order, (b) second order and (c) third order sections of the Quebrada Mquina. There were 168 individuals in the first, 210 indivi duals in the second, and 142 individuals in the third stream order, respectively. Figure 2. Mean taxa rich ness for each stream order of the Quebrada Mquina (a) (b)

PAGE 10

RCC applicability to a lower montane stream Picetti 10 Figure 3. Relative abundances of individuals of the first stream order of the Quebrada Mquina Figure 4. Relative abundances of individuals of the second stream order of the Quebrada Mquina

PAGE 11

RCC applicability to a lower montane stream Picetti 11 Figure 5. Relative abundances of individuals of the third stream order of the Quebrada Mquina Figure 6. Mean relative abundances of individuals for each stream order of the Quebrada Mquina

PAGE 12

Table 1. Study site physical characteri stics of the Quebrada Mquina Site Stream order Elevation (m) Mean channel width (m) Mean water depth (cm) Water Temp. (C) Stream velocity (cm/sec) % canopy cover 1 1 1545 1.3 6.3 15 Zero* 81 100 2 1 1530 0.7 9.5 16 22.6 81 100 3 1 1550 2.2 13.7 15 39.3** 81 100 1 2 1530 1.6 15.9 16 29.5** 81 100 2 2 1510 2.6 5.5 15 8.1** 61 80 3 2 1480 3.8 16.7 15 27.1** 81 100 1 3 1460 1.4 15.4 16 36.6** 81 100 2 3 1450 2.7 13.2 16 15.7** 81 100 3 3 1450 3.9 14.3 15 37.8 81 100 All microhabitats at this site were static pools and thus had no velocity ** Sites that contain at least one static pool so velocity was averaged for non pool microhabitats Table 2. Substrate types of the Quebrada Mquina* Site Stream order Maximum (largest) substrate size Most dominant substrate size Second most dominant substrate size 1 1 Boulders Large cobble/bould ers Small cobble 2 1 Boulders Very coarse sand Boulders 3 1 Boulders Small cobble Large cobble/boulders 1 2 Boulders Small/large cobble Coarse sand 2 2 Boulders Small cobble Large cobble/boulders 3 2 Boulders Small cobble Large cobble 1 3 Boulders Small/large cobble Boulders 2 3 Boulders Small cobble Large cobble 3 3 Boulders Boulders Large cobble Substra te classifications based on Table 3.3 on p. 60 of Stream Ecology: Structure and function of running waters by J.D. Allan (1995)

PAGE 13

FAMILY GENUS FFG Elmidae Macrelmis collector gather er Ptilodactylidae Anchytarsus collector gatherer Staphylinidae undetermined predator Chironomidae Morphospecies #1 collector gatherer Chironomidae Morphospecies #2 collector gatherer Chironomidae Morphospecies #3 collector gatherer Chironomidae Morp hospecies #4 collector gatherer Chironomidae Morphospecies #5 collector gatherer Chironomidae Morphospecies #6 collector gatherer Dolichopodidae Morphospecies #1 shredder Simuliidae Simulium collector filterer Tipulidae Hexatoma predator Tipulidae Mo rphospecies #1 predator Tipulidae Morphospecies #2 predator Leptohyphidae Tricorythodes collector gatherer Leptophlebiidae Thraulodes collector gatherer Naucoridae Pelocoris predator Veliidae Rhagovelia predator Calopterygidae Hetaerina predator Coenagrionidae Argia predator Gomphidae Phyllogomphoides predator Gomphidae Progomphus predator Libellulidae Morphospecies #1 predator Polythoridae Polythora predator Perlidae Anacroneuria shredder/predator Calamoceratidae Phylloicus collector gather er Hydrobiosidae Atopsyche predator Hydropsychidae Leptonema collector filterer Hydropsychidae Smicridea collector filterer Hydroptilidae Hydroptila collector gatherer Odontoceridae Marilia collector gatherer Philopotamidae Chimarra collector gathere r Planariidae undetermined predator Order Amphipoda undetermined shredder Order Decapoda undetermined *not included in FFG data

PAGE 14

RCC applicability to a lower montane stream Picetti 14 Table 4 Shannon Wiener Diversity Values Order Maximum Shannon diversity (H max ) Evenness ( 1 0.81 1.34 0.60 2 0.84 1.41 0.60 3 1.07 1.40 0.77